Resin molded bodies (hereinafter simply referred to as molded bodies) made of plastics are widely used for members such as various containers and daily commodities. In consideration of formability, mechanical strength, recyclability, and heat resistance, polyolefins and polyesters are used for the molded bodies in many cases. In recent years, since an aesthetically pleasing appearance and good design properties have been required for resin molded bodies and these are major appeal factors when consumers buy products, a luxurious feeling has been conveyed by imparting, for example, pearl-like gloss, to a cap of a shampoo bottle or a beverage bottle.
As a method of imparting pearl-like gloss to a molded body, in addition to a method of applying a pearl-like material such as a titanium-based pearl pigment to a surface of a molded body or kneading it into a molded body, a method of blending polymers having different refractive indexes is known. In the former method, light beams are reflected at a pearl-like gloss (for example, mica) surface, they interfere with each other, and thus pearl-like gloss is exhibited. On the other hand, in the latter method, light beams are reflected and refracted at interfaces between resins having different refractive indexes, they interfere with each other, and thus pearl-like gloss is obtained. In the latter method, a resin composition in which a polyester and a polyolefin are blended is disclosed in Patent document 1.